Osteopetrosis - hypogammaglobulinemia

Receptor activator of nuclear factor κ B (RANK), also known as TRANCE receptor or TNFRSF11A, is a member of the tumor necrosis factor receptor (TNFR) molecular sub-family. RANK is the receptor for RANK-Ligand (RANKL) and part of the RANK/RANKL/OPG signaling pathway that regulates osteoclast differentiation and activation. [Source: Wikipedia ]

Autosomal recessive osteoclast-poor osteopetrosis with hypogammaglobulinemia
Autosomal recessive osteopetrosis type 7
OrphaNet reference
Osteopetrosis - hypogammaglobulinemia 
May Cause